Thyroxine produced by:

Options

A. Pituitary gland
B. Thyroid gland
C. Endocrine gland
D. None of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Thyroxine**: Begin by recognizing that thyroxine is a hormone that plays a crucial role in regulating the body's metabolic rate.

2. **Identifying the Source**: The question asks where thyroxine is produced. We need to evaluate the options provided.

3. **Evaluating the Options**:
- **Option 1: Pituitary Gland**: This gland is often referred to as the "master gland" because it regulates other glands in the endocrine system. However, it does not produce thyroxine.
- **Option 2: Thyroid Gland**: This is the correct option. The thyroid gland is responsible for the production of thyroxine.
- **Option 3: Endocrine Gland**: While the thyroid is indeed an endocrine gland, this option is too broad and does not specifically identify the source of thyroxine.
- **Option 4: None of These**: This option is incorrect as we have identified the thyroid gland as the source.

4. **Conclusion**: Based on the evaluation, the correct answer is that thyroxine is produced by the **thyroid gland**.

**Final Answer**: Thyroxine is produced by the thyroid gland.

---